[PATCH xserver 1/2] xwayland: Apply "last pointer window" check only to the pointer device

[Carlos Garnacho]

The checks in xwayland's XYToWindow handler pretty much assumes that the
sprite is managed by the wl_pointer, which is not entirely right, given
1) The Virtual Core Pointer may be controlled from other interfaces, and
2) there may be other SpriteRecs than the VCP's.

This makes XYToWindow calls return a sprite trace with just the root
window if any of those two assumptions are broken, eg. on touch events.

So turn the check upside down, first assume that the default XYToWindow
proc behavior is right, and later cut down the spriteTrace if the
current device happens to be the pointer. We work our way to the
device's lastSlave here so as not to break assumption #1 above.

Also, simplify the actual nested call to XYToWindow, the method pointer
in ScreenPtr was reinstaurated before calling, and moved back to
xwl_screen domain afterwards. This seems kind of pointless, as we have
the function pointer anyway.

Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
---
 hw/xwayland/xwayland-input.c | 64 ++++++++++++++++++++++++++------------------
 1 file changed, 38 insertions(+), 26 deletions(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index 32cfb35..9b385dc 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -945,43 +945,55 @@ DDXRingBell(int volume, int pitch, int duration)
 {
 }
 
-static WindowPtr
-xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
+static DeviceIntPtr
+sprite_get_last_active_device(SpritePtr sprite, struct xwl_seat **xwl_seat)
 {
-    struct xwl_seat *xwl_seat = NULL;
     DeviceIntPtr device;
-    WindowPtr ret;
 
     for (device = inputInfo.devices; device; device = device->next) {
-        if (device->deviceProc == xwl_pointer_proc &&
-            device->spriteInfo->sprite == sprite) {
-            xwl_seat = device->public.devicePrivate;
+        /* Ignore non-wayland devices */
+        if (device->deviceProc != xwl_pointer_proc &&
+            device->deviceProc != xwl_touch_proc &&
+            device->deviceProc != xwl_keyboard_proc)
+            continue;
+
+        if (device->spriteInfo->sprite == sprite)
             break;
-        }
     }
 
-    if (xwl_seat == NULL) {
-        sprite->spriteTraceGood = 1;
-        return sprite->spriteTrace[0];
-    }
+    if (!device || IsFloating(device))
+        return NULL;
 
-    screen->XYToWindow = xwl_seat->xwl_screen->XYToWindow;
-    ret = screen->XYToWindow(screen, sprite, x, y);
-    xwl_seat->xwl_screen->XYToWindow = screen->XYToWindow;
-    screen->XYToWindow = xwl_xy_to_window;
+    *xwl_seat = device->public.devicePrivate;
 
-    /* If the pointer has left the Wayland surface but the DIX still
-     * finds the pointer within the previous X11 window, it means that
-     * the pointer has crossed to another native Wayland window, in this
-     * case, pretend we entered the root window so that a LeaveNotify
-     * event is emitted.
+    /* We do want the last active slave, we only check on slave xwayland devices
+     * so we can find out the xwl_seat, but those don't actually own their
+     * sprite, so the match doesn't mean a lot.
      */
-    if (xwl_seat->focus_window == NULL && xwl_seat->last_xwindow == ret) {
-        sprite->spriteTraceGood = 1;
-        return sprite->spriteTrace[0];
-    }
+    return device->master->lastSlave;
+}
 
-    xwl_seat->last_xwindow = ret;
+static WindowPtr
+xwl_xy_to_window(ScreenPtr screen, SpritePtr sprite, int x, int y)
+{
+    struct xwl_seat *xwl_seat = NULL;
+    struct xwl_screen *xwl_screen;
+    DeviceIntPtr device;
+    WindowPtr ret;
+
+    xwl_screen = xwl_screen_get(screen);
+    ret = xwl_screen->XYToWindow(screen, sprite, x, y);
+
+    device = sprite_get_last_active_device(sprite, &xwl_seat);
+
+    if (device && xwl_seat && xwl_seat->pointer == device) {
+        if (xwl_seat->focus_window == NULL && xwl_seat->last_xwindow == ret) {
+            sprite->spriteTraceGood = 1;
+            return sprite->spriteTrace[0];
+        }
+
+        xwl_seat->last_xwindow = ret;
+    }
 
     return ret;
 }
-- 
2.10.0